I use dmg to raid bosses. They took my name and sent it to the game. I know because I'm in a group. Now I'm waiting to see if I'll get banned or not.Alright, so here the thing.
Use the multiplier for farming mats or main story, as long as it's not raid/anything multiplayer mode.
Play raid naturally, not even with def multiplier nor skill cost. I know you'll not getting good final result, but it's better that way than risking yourself.